Heads,LIM,UIM(supercharger), Fuel Rails, Injectors (recommended, you may be able to make due with L36 inj, I did for about a week), you need the Ignition control module bracket, the SC belt tensioner, the idler tower, the L67 Harmonic balancer, Gaskets, new head bolts (i'd reccomend studs) new rocker bolts, tune, L67 Map and l36 to l67 map connector adapter... and more that i'm forgetting see my faq's and a write up (not mine) on GPF:
http://www.grandprixforums.net/f17/top-swap-info-faqs-also-lots-7763.html
and let me know of any more specific questions, there are many other members here that know more than me, but I have top swaped, so I did do a good bit o' reaserch before the action